Dyeing of acrylonitrile polymeric structures



Patented Dec. 18, 1962 3,069,221 DYEING F ACRYLONITRILE POLYMERIC STRUCTURES Julius Hermes, 905 J efierson Circle, Martiusville, Va. No Drawing. Filed June 30, 1959, Ser. No. 823,853 9 Claims. or. 8-92) This invention relates to the dyeing of polymeric structures containing acrylonitrile. More particularly, it relates to a new and eifective process for improving the rate and depth of dyeability of acrylonitrile polymeric structures to produce uniformly dyed Structures having superior color fastness.

Polymers containing a high percentage of acrylonitrile do not readily accept dyes under normal dyeing conditions. Consequently, deep and brilliant shades of dyed acrylonitrile have been. difiicult to obtain, as well as color fastness, due to the lack of dye penetration of these types of polymer structures.

In order to overcome these and other disadvantages in the dyeing of acrylonitrile polymer structures and to produce a rapid and permanent dyeing by deep penetration, this invention contemplates the treatment of polymer structures containing acrylonitrile in a heated aqueous bath to which has been added a small percentage of alkylene carbonate. The dye bath containing alkylene carbonate is maintained at elevated temperatures, such as temperature near or at its boiling point. It has been found that best results are obtained when dye bath is maintained at boiling temperature; however, lower temperature baths may be used which, of course, require slightly longer contact time to produce the desired shade or hue of the dyed structure.

Advantageously the dyeing bath can be maintained at a pH of about 2 to 8 and acid may be included to bring the bath to a lower pH if an acidic bath is desired. Excellent dyeing results have been obtained when the pH is normal or close thereto. After treatment in the dye bath, the dyed structure may be advantageously washed in water to remove alkylene carbonate solution from the surface of the dyed structure. The water bath may be slightly acid or contain materials which will hydrolyze the alkylene carbonate.

Typical of the polymeric material which may be dye treated by the process of this invention are the well-known acrylonitrile type polymeric structures which include those containing at least 50 percent by weight acrylonitrile units in the polymer chain; for example, polyacrylonitrile and its copolymers and interpolymers of acrylonitrile with other polymerizable monomers. These monomers include, among others, vinyl acetate, vinyl chloride, acrylic and methacrylic acids or derivatives and homologues thereof, styrene, methyl vinyl ketone, vinyl pyridines, such as 2-vinyl, 4-vinyl, 5-ethyl-2-vinyl or 2-methyl-5-vinyl pyridine and isobutylene or other similar polymerizable hydrocarbons.

Exemplary of alkylene carbonates used in the dye baths of this invention are the alkylene carbonates having 3 to 5 carbon atoms. Among the more important of these carbonates are ethylene carbonate, propylene carbonate, trimethylene carbonate, tetramethylene carbonate, 2,3- butylene carbonate, glycerine carbonate, and the like, propylene carbonate being preferred.

Typical dyestuffs which can be used to dye acrylonitrile polymer structure include some of the acid dyes, basic dyes, disperse dyes and the like. It has been found that these dyes exhaust rapidly from the dye bath when the solution is neutral or close thereto. However, good dye exhaustion from the bath is provided when the pH ranges from 2 to about 8. Any acid may be used to provide the acid dye bath. For this purpose either an organic or an inorganic acid may be used.

The aqueous dye bath contains a small percentage of the dyestufr' dispersed therethrough to effect dyeing of the polymer structure. It has been found that the shade of color can be controlled by the concentration of the alkylene carbonate in the bath. For example, alkylene carbonate in the range of 2 to 20 percent by volume produces excellent dye exhaustion from the bath within short contact time. Where lighter shades are desired the lower portion of the range can be used, the percentage of the alkylene carbonate used depending on the shade of dyeing desired. -It has also been found that after the upper portion of the range hasbeen reached, the addition of more alkylene carbonate does not substantially aifect dye exhaustion.

The aqueous dye bath heretofore described maintained at approximately boiling temperature imparts to polymer structure of acrylonitrile excellent penetration of the dye producing full brilliance of color within a short period of contact time. It has been found that temperatures from about C. produce good results. Of course, lower temperatures may be used, but the contact time would be increased. The preferred temperature is at the boiling point of the bath where the most rapid dyeing of the structure takes place, requiring as little as 5 to 20 seconds contact time for the complete dyeing of the polymeric material. Thus, it will be appreciated that by the process of this invention rapid dye exhaustion in the dyeing of acrylonitrile polymer structures within a matter of seconds is accomplished without the loss of dyeing efiiciency and depth of color.

The invention will be more clearly understood by reference to the following examples which are given for purposes of illustration and are not to be construed in any sense as limitative of the invention.

Example I A dye bath was prepared by the addition of 50 cc. of propylene carbonate to 450 cc. of water. Two grams of Victoria green dyestuif was then added and the bath heated until boiling.

A colorless sample of fabric of the Orlon-type (acrylonitrile-methacrylic acid) was immersed in the dye bath for a period of 15 seconds. After immersion, the fabric was washed and dried and upon examination it was found to have a very deep and brilliant green coloration with a high degree of dye penetration. On further testing of the fabric, it was found to have excellent fastness properties and no change in its original physical properties had occurred.

Example II Example III The dye bath as described in Example II was prepared, except that 10 cc. of propylene carbonate and 490 cc. of water was used. A sample of undyed Orlon multifilament tow was then immersed in the hot bath for a period of 10 seconds. The tow was dried and exhibited a pleasant pink coloration. Further testing showed that the dyed tow was color fast.

Example IV Using the same fabric, conditions, and bath as described in Example II, except that glycerine carbonate and two grams of Sevron Blue 5 G (Dupont) was used. The fabric after dyeing had a deep brilliant greenish blue color and exhibited excellent fastness. No change in the original physical characteristics of the fabric was found to exist.

Example V As described in Example I, the dye bath was prepared using 75 cc. of ethylene carbonate, 425 cc. of water and 2 grams of Latyl Violet R (Dupont). The fabric dyed to a deep reddish violet. Upon testing, the dyed structure was found to have excellent fastness properties.

Example VI As described in Example I, the dye bath was prepared except that 50 cc. of propylene carbonate, 450 cc. of water and 1 gram of Quinoline Yellow N (Dupont) was used. A length of Orlon type film 5 mils in thickness was immersed in the bath for a period of seconds. The film when washed and dried had a bright yellow coloration and excellent color fastness. No change of its original physical properties were found to exist.

Example VII As described in the above example several tests were conducted in which the pH of the dye bath was maintained between 2 and 7 by the inclusion of acetic and phosphoric acid.

It will be appreciated that acrylonitrile-type polymeric structures in any form, such as fabrics, yarns, films, and the like, can be quickly and permanently dyed by the process of this invention and with the use of commercial dyeing apparatus. Also, deeper, more penetrated dyeing is effected than was heretofore obtainable, and dyed structures are provided which are color fast and resist crocking. Thus, structures dyed by this process resist color degradation by scratching or scufiing of the surface without affecting the original physical and chemical properties. A particularly advantageous feature of the process of this invention is that fast and economical continuous dyeing can be accomplished since the structure is required to remain in the dye bath for a matter of seconds to produce deep dyeing of the polymer structures.

What is claimed is:

1. A process for rapid dyeing of preformed polymeric structures after formation containing at least 50 percent by weight acrylonitrile which comprises immersing the structure in a heated aqueous bath maintained at a temperature above 80 degrees C. for a period of from 5 to 20 seconds, said bath including a dyestuif and frorn.2 to 20 percent by volume of an alkylene carbonate having from 3 to 5 carbon atoms.

2. The process as claimed in claim 1 in which said bath has a pH from about 2 to about 8.

3. The process as claimed in claim 1 in which the temperature of said bath is at its boiling point.

4. The process as claimed in claim 1 in which thedycd structure is washed anddricd to remove the presence of said alkylene carbonate after immersion in said dye bath.

5. The process as claimed in claim 1 in which the alkylene carbonate remaining on said structure after treating in the dye bath is hydrolyzed.

6. The process as claimed in claim 1 in which the shade of color is produced by varying said concentration of alkylene carbonate.

7. A process for rapid dyeing of preformed polymeric structures after formation containing at least percent by weight acrylonitrile which comprises immersing the structure in a heated aqueous bath at a temperature above C. for a period from 10 to 20 seconds, said bath including a dyestuff and from 2 to 20 percent by volume of ethylene carbonate, the bath having a pH of from about 2 to about 8.

8. A process for rapid dyeing of preformed polymeric structures after formation containing at least 50 percent by weight of acrylonitrile which comprises immersing the structure in a heated aqueous bath at a temperature above 80 C. for a period of from 10 to 20 seconds, said bath including a dyestuff and from 2 to 20 percent by volume propylene carbonate, the bath having a pH of from about 2 to about 8.

9. A process for rapid dyeing of preformed polymeric structures after formation containing at least 50 percent by weight acrylonitrile which comprises immersing the structure in a heated aqueous bath at a temperature above 80 C. for a period of from 10 to 20 seconds, said bath including a dyestuff and from 2 to 20 percent by volume glycerine carbonate, the bath having a pH of from about 2 to about 8.

References Cited in the file of this patent UNITED STATES PATENTS 2,569,470 Hagemeyer Oct. 2, 1951 2,716,586 Terpay Aug. 30, 1955 2,717,823 Lowe Sept. 13, 1955 2,733,978 Jones Feb. 7, 1956 2,774,648 Mecco Dec. 18, 1956 FOREIGN PATENTS 734,974 Great Britain Aug. 10, 1955 OTHER REFERENCES 41Eturnthall: Amer. Dyest. Rep, May 18, 1959, pages 

1. A PROCESS FOR RAPID DYEING OF PREFORMED POLYMERIC STRUCTURES AFTER FORMATION CONTAINING AT LEAST 50 PERCENT BY WEIGHT ACRYLONITRILE WHICH COMPRISES IMMERSING THE STRUCTURE IN A HEATED AQUEOUS BATH MAINTINED AT A TEMPERATURE ABOVE 80 DEGREES C. FOR A PERIOD OF FROM 5 TO 20 SECONDS, SAID BATH INCLUDING A DYESTUFF AND FROM 2 TO 20 PERCENT BY VOLUME OF AN ALKYLENE CARBONATES HAVING FROM 3 TO 5 CARBON ATOMS. 